1. Field of the Invention
The present invention concerns a method for automated evaluation of a three-dimensional image of a laterally-symmetric organ system as well as a medical image data acquisition system and a computer program for this purpose.
2. Description of the Prior Art
Data acquisition methods in which a three-dimensional data set or image of organ systems of a patient to be examined is produced are well known in medical imaging due to the exceptional diagnostic possibilities. The methods employed (such as, for example, computed tomography or magnetic resonance tomography) generate large data sets. For example, modern computed tomography systems produce dozens of slice image exposures in a few hundred milliseconds. The large number of exposures that arise can often be evaluated by a radiologist only with a very large expenditure of time. The risk of overlooking findings increases given the evaluation of large data sets.
For the evaluation of laterally-symmetric organs situated in a laterally-symmetrical manner, it is helpful and often even necessary for the radiologist to analyze both sides of the organ in comparison with one another. Often only a laterally different assessment indicates pathologies or (in the reverse case) an apparently suspect finding in one half of the organ system turns out to be a harmless normal variant when it also occurs in the other half of the organ system.
Large data sets must also be evaluated in for oncological questions, since often the entire body of the patient, or at least large portions thereof, are to be scanned for indicative of metastasy lesions. A typical example is plasmocytoma, which can manifest at many points of the skeleton. Laterally-different findings here are considered as particularly suspect with regard to a possible metastasy
As a result, there exists a need for automatic evaluation methods that support the user (in particular the radiologist) by marking suspect points to which the user subsequently directs his or her attention.
A method for automatic generation of result images of an examination subject using slice image data is disclosed in DE 103 57 205 A1 and in the corresponding US 2005/14852 A1. A target structure is initially determined dependent on a diagnostic question and an anatomical normal model, the geometry of which can be varied using the model parameters, is automatically adapted to the target structure. A segmentation ensues from which the adapted normal model and relevant anatomical structures of the examination subject are separated with regard to the relevant diagnostic question, by such structures being identified with the aid of the normal model. The relevant anatomical structures are subsequently separately visualized and/or stored for a later visualization.
DE 199 20 300 A1 discloses a method for tracking pathological variations in the human body using magnetic resonance scanners, wherein a 3D image data set is automatically compared with old image data sets of the same patient and/or with anatomical atlases for determination of pathological variations.